This relates generally to imaging systems and, more particularly, to imaging systems with back-side illuminated pixels.
Modern electronic devices such as cellular telephones, cameras, and computers often use digital image sensors. Imager sensors (sometimes referred to as imagers) may be formed from a two-dimensional array of image sensing pixels. Each pixel includes a photosensitive element that receives incident photons (light) and converts the photons into electrical signals. Image sensors are sometimes designed to provide images to electronic devices using a Joint Photographic Experts Group (JPEG) format.
Some conventional image sensors may be able to operate in a high dynamic range (HDR) mode. HDR operation is usually accomplished in image sensors by assigning alternate rows of pixels different integration times. However, assigning two different integration times to different rows in the image sensor array usually sacrifices resolution. Additionally, it may be difficult to achieve a very high dynamic range (e.g., 100 dB or more) using this method.
It would therefore be desirable to be able to provide improved high dynamic range operation in image sensors.